Look for a 4-door genuine M-Tech 2 kit - it will fit the touring, except the boot-spoiler.
Don't bother with relicas - rubbish quality.
Mind you, the kit could be anything between Ԛ£300 to Ԛ£500
And as for seats, well, if you are looking for the recaro-style Sport seats, you probably might find it easier to get them from a 2-door, like a Sport. Haven't seen many in 4-door cars.
Keep an eye here on the Zone, or you can try specialist BMW breakers like
http://www.fabdirect.com/